Explosive



June 30, 1925. 1,543,798

A. c. scoT'r EXPLOSIVE Filed Aug. 26, 1924 Patented June 30, 1925.

umrso STATES 1,543,798 ENT ojsFFiE,

nnaxammn CRUICKSHANK sco'r'i I or emu-r, WALES, ASSIGNOB '10 mixco mmmm), or LONDON, ENGLAND, A BRITISH COMPANY.

EXPLOSIVE.

Application filed August 20, 1924. Serial No. 734,210.

To all whom it may concern:

Be it known that I, ALnxANnm CRUIcK- simNK Sco'rr, British subject, engineer, residin at Cardiff, in Wales, have invented certain new and useful Improvements in Explosives, of which the following is a specification.

This invention consists of improvements in or relating to explosives, the object being to provide an effective explosive of the Sprengel type, free from the disadvantages that have occurred in he use of explosives of quently not homogeneously penetrated by the liquid hydrocarbon employed as fuel. Moreover, in order to render the body of the cartridge as porous as possible and thus fa' cilitate penetration of the fuel, the chlorate is packed only loosely, the specific gravity of the charge in the cartridge in the case of potassium chlorate being usually about 1.3, whereasthe density of individual crystals of potassium chlorate is about 2.34. Consequently the amount of explosive in a given space is a minimum, and the intensity of the resultant explosion is not very high.

I have found that advantageous results can be secured by packing the crystals closely and providing a-charge of which the 'crystals are not of uniform size but vary sufficiently for the smaller crystals to fill up the spaces between the larger ones so that the density of the charge is raised. In the case of potassium chlorate the densit may be raised to as much as 1.9. By using as the fuel a liquid which has the property of creeping or spreading over the surface of the crystals, it is then possible to secure an,

effective and unlform penetration of the liquid. The intensity of the explosion is increased very considerably both because of the greater density and of the greater uniformity of the char The closer packing of the crystals afl'or s a fi'ne capillary structure in the body of the cartridge, which assists liqulds of the kind referred to penetrate.

According to this invention there is prov1ded in or for use in an explosive charge, a cartridge consisting of a porous case and crystals therein of the kind described which are socrushed and packed for the purpose descrlbed that the volume of the voids between the crystals does not exceed twentytwo per cent of the total volume occupied b the crystals. To pack the crystals to sue a density involves the application of pressure as hereinafter described.

Preferably the crystals are ground to a size less than 60 mesh and have at least 30% of crystals of a size less in linear dimensions than 200 mesh. It is found that by grindmg to these dimensions the charge can easily be packed to the required density and with-' out the use of an undue amount of pressure such as would burst the porous case.

Before the cartridge is used there is in troduced a, quantity amounting to from 8 to 12% of the weight of the crystals, of a stable mobile liquid hydrocarbon such as parafiin. oil (kerosene) which ssesses the property of creeping or spreading over the 35 surface of the crystals, forming a very thin film. Sufiicient void space must be left between the crystals to accommodate the required quantity of oil. If paraflin oil is employed it must be of a kind which will creep over the crystals. For example, Russian petroleum has been found suitable for the purpose. This oil contains a certain proportion of oils of the series C H It is found that paraflin which is free of hydrocarbons other than those of the paraffin series of the type GnH does not tend to creep in this wa but it may be rendered suitable for use y the addition of a small proportion of certain. hydrocarbons of the nzene ring series containing a plurality of methyl radlcles such as xylol C H,(GH The proportion of xylol employed may be up to 10% of the weight of hydrocarbon used. Instead of xylol, Persian fuel oil whizh contains asphaltic compounds may be use The-invention includes a cartridge as above described characterized by the provision of a central axial recess lined with paper (or no metal, celluloid or the like) which is perforated or otherwise pervious to the lixfuid hydrocarbon. In this way the capacity of the inner c linder may be made equal to the volume of ydrocarbon required to be introduced to pre are the cartridge for use, and the hydrocar n can be introduced into the cartridge by mere] filling the central chain}; ber therewith and allowing the liquid tsoak into the cartridge. It is preferred, however, to employ a solid cartridge with a case the external walls of which are porous, and to pour the proper proportion of hydrocarbon over the same.

The invention further includes a method for the manufacture of hollow cartridges as above described which consists in securing together an outer cartrid case closed at one end (preferably ma e of impervious material) and an inner cylinder co-axial therewith which is perforatedwor otherwise pervious to liquid, and packing cr stals of an oxygen-carrying substance, sue as potassium chlorate, into the annular space between the cartridge and the porous inner cylinder by means of an annular feed worm which fits the annular space and is' simultaneously oscillated longitudinally and r0- tated about the axis of the cartridge. 7

Preferably the inner cylinder is supported upon a mandrel during the filling operation and the mandrel is removed after the filling operation is completed.

If it is desired to storethe ch orate cartridge for some time before the hydrocarbon is added thereto, the cartridge can be wrapped in a layer of waterproof fabric, such as waterproof paper or waterproof linen. The cartridge, after the hydrocarbon has soaked into the powder, may be reintroduced into the waterproof casing, theedges and ends of which are sealed 0 wn sa by a suitable glue.

e following is one example of carrying the invention into efl'ect.

Potassium chlorate is either ground or obtained in the form of fine crystals of the mesh already defined. That is to say the crystals will all pass a mesh screen and 30% of them wil pass 200-mesh. The c stals should be free from moisture. ale paper cartridge may be made u perforated with fine holes of a iameter of 0.01.04 inches the perforations being so spaced that 50 to 1 square inch.

Alternatively, the cartrid e maybe made of material of a porous c aracter which must, however, be strong enough to withstand the pressure-produced during'filling. The cartri is introduced into a filling machine an the chlorate crystals are firmly packed therein, the density varying from 1.6 to 1.9. The cartridge is then closed at.

the free end. convenient diameter for the of paper v perforations occupy cartridge is about one inch, and the length of the cartridge varies according to the charge, a typical example being a cartridge of six inches in length. A known ,type of filling machine having a helical feeding work can be em loyed, similar in this re? spect to that hereinafter described for, filling hollow cartridges.

Normally the cartridge is then enclosed I in 'a covering of waterproof paper. cartridges in this state are non-explosive and can be transported anywhere without the risks attending the transport of ordinary e losives.

vhen the second on the potassium chlorate present, is ured The stage in the manufac-' ture of the explosive is to becarried out,

over the cartridge, and the arafiin oi soaks right in. The cartridge is t en covered with a sheath of waterproof aper or waterproof fabric as before, the es and ends being sealed with a suitable glue. Sufiicient'time must be allowed for the paraflin oil to creep all over the crystals before the cartridge is used; the cartridges are referably allowed to standfor 24 hours he ore they are ready for' use. I

The explosive can be detonated by an usual (letonator (such as a No. 6 detonatori which has 15.5 grains of composition containing mercury fulminate.

' An alternative method for use where it is desired to" employ hollow cartridges is as follows Referring to the aocom anying drawing, Figure 1, an outer cartri go or cylinder 10 is referably made'of impervious material, sudh as waterproof and oilproof paper or fabric. A convenient diameter for the cartridge is about 1 inch, and the length of the cartridge varies according to the charge, a typical example being a cartridge of 6 inches in length. Thismrtridfie is closed at one end'as shown at 11, and t at end and the edges are secured by a suitable glue. co-axially within this cartridge is secured a cylinder; 12 of paper. This paper may be provided with fine perforations and' maybe wrapped for severa turns around a cylindrical mandrel 13, which conveniently has a diameter of one-quarter inch or less, for ex ample the same diameter as the detonator which is subsequently to be introduced matically indicated in the drawing into a filling machine provided with a helical blade or worm 14 which fits between the two cylinof the cartridge, and the chlorate is then fed ders. This feeding worm has a shank 15 mounted so that it can be reciprocated longitudinally along its own axis and also rotated. Suitable well known'means are provided for effecting such longitudinal reciprocation and simultaneous rotation of the feed worm, which means also allow it to be gradually withdra'wnjrom the cartridge during such movement. cartridge by the funnel 16 and are packed by the feed worm 14 as tightly as possible. An annular disc of waterand oil-proof paper, out so as to fit tightly inside the cartridge case and having a central hole of the correct size for the tube to pass through, is then pressed down close to the to layer of the salts and is secured to the inside of the cartridge by suitable glue so as to form a waterand oil-tight joint. The niandrel. 13 may then be withdrawn,

Alternatively, As shown in Figure 2, the axle of the feeding worm 14 may be provided with a solid cylindrical core or man-' drel 17 of slightly less diameter than the core of the hollow worm.

As a further alternative, one end of the perforated tube 12 of the cartridge may be glued or otherwise fastened normally to a disc of paper 18 (Figure 3) which will fit inside the outer tube 10 of the cartridge. Before the filling of the chlorate commences, the perforated tube 12 may be introduced into the hollow axle of the feeding worm 14,

the solid core or mandrel 17 (if this is used) fitting inside the perforated tube. The feeding worm 14 is then introduced into the cartridge so that the disc 18 attached to the end of the perforated tube is at the bottom and packed (by oscillating and rotating the worm while withdrawing it) into the space between the perforated tube 12 and the outer tube 10 of the cartridge. While the feeding worm is being withdrawn the disc of paper attached to the end of the perforated tube is held down at the bottom of the cartridge by the chlorate crystals which are packed above it, and the tube is left in an axial position after filling is complete. An

annular disc of waterand oil-proof paper may then be ressed down close to the top layer of the c lorate, and secured to the inside of the cartridge by'suitable glue so as to form a waterand oil-tight joint.

At this stage, by whichever method the cartridges have been filled, the free end of the outer cylinder may be folded over and temporarily closed.

When the second stage in the manufacture of the explosive is to be carried out, the end of the outer cartridge is opened out. The quantity of parafiin oil (kerosene) required for that particular cart-ridge and amounting preferably to 10% of the chlorate present, is poured into the central cavity, and the The crystals are fed into the paraflin oil soaks right into the cartridge. The outer cartridge is then closed down and it may be sealed with a suitable glue. The perforations in the inner c linder may be varied in size or number a ong the length. of the inner cylinder in such a manner as to ensure uniform distribution of the paraflin oil in the cartridge.

A measure of the volume of the voids in any given cartridge can be obtained by comparing the weight of the cartridge as a whole with the weight which it would have, calculated on the assumption that the space was completely filled with a substance of the same density as the substance of the crystals. Thus the density of .potassium .chlorate crystals is 2.34. If the density of the space in the cartridge which is packed with potassium chlorate crystals be equal to 1.9 then, the volume of the voids will be equal to of that space. In the followin claims the expression crystals of the kin described is intended to be limited to crystals of potassium chlorate, potassium perchlorate, an ammonium perchlorate, or mlxtures containin these crystals.

What I claim as my invention and desire to secure by Letters Patent is 1.' A cartridge'consisting of a porous case and crystals therein of the kind described which are so crushed .and packed for the purposedescribed that vthe volumeof the voids between the crystals does not exceed thirty-two per cent of the total volume occupied by the crystals and yet is adequate to accommodate the necessary quantity of hydrocarbon.

2. A cartridge consisting of a porous case and crystals therein of the kind described which are so crushed and packed for the purpose described that the volume of the voids between the crystals does not exceed nineteen per cent of the total volume occupied by the crystals and yet is adequate to accommodate the necessary quantity of hydrocarbon.

3. A cartridge consisting of a porous case packed under pressure with crystals of the kind described ground for the purpose described to a size less than 60 mesh and having at least 30% of crystals of a size less than 200 mesh.

1. A cartridge consisting of a porous case and crystals therein of the kind described which are so crushed and packed for the purpose described that the volume of the -voids between the crystals does not exceed thirty-two per cent of the total volume occupied by the crystals and into which has been introduced a quantity, amounting to from eight to twelve per cent of the weight of the crystals, of a stable mobile .liquid'hydm carbon such as parafiin oil (kerosene) of the of the crystals," of a stable 'mobile liquid hydrocarbon such as 'paraflin-oiI (kerosene) of the-kind described which e' p y y Q eP ngnrrm' ins-br a ace ofthe crystals, a yery thin 6. cartridge acked under pressure with crystalsloffthe scribed to asiz'e less than inesh and hav-f ing at least 30% of, crystal's of- -'a"size less' than 200 mesh: and intoywhich .hasjbecn introducedfa quantity, amounting to from eight to twelve per -cent*oi,'thejweight,of the crystals, of a stable mobile liquid'hydrm carbon such vas'paraflinoil (kerosene) of the. kind described which ssessestheg'property" of creeping -or sprea ing over thesurfa'ceof the crystals, forming a We thin film.

7. A cartrid e consistin o a rous case and crystals t erein of t e kin described which are so crushed and packed for the pn se described that the volume of the voi s between the crystals does not exceed thirty-two per cent of the total volume occupied by the crystals and into which has been introduced a hydrocarbon which contains a benezene derivative containing a plurality of methyl radicles.

' 8. A cartridge consistlng of a orous case and crystals t erein of the kin described which are so crushed and packed for the pur described that the volume of the voi s between the crystals does not exceed thirty-two per cent of the total volume occupied by, the crystals and into which has been introduced a hydrocarbon which contains xylol.

9; A cartridge consistin of a casing and crystals therein of the kin described which are-so crushed and packed for. the purpose described, that the volume of the voids between the crystals does not exceed thirtytwo' percent of the total volume occupied by the crystals, the casing being rendered porous by. fine perforations in the walls of the casing toosmall to permit of the crystals.

cartridge. consisting of a casing and crystals therein of the kind described which are so crushed and packed ,for the purpose rous case- 4 nd described ground "for the purpose de':

described that the volume of the voids between the crgstals does not'exceed nineteen per cent of t e total volume occupied by the crystals,the casing being rendered porous by fine perforations in the. walls of the casing too small to permit escape of-the' '11. A cartridge comprising a casing in the formjof an externalshell and a central axial tube therein so much smaller than the shell-as to leave a space between the shell and the' tub'e, said tube being pervious to liquid hydrocarbon, and crystals between the casing .;and the tube which are so crushed and acked for the purpose dethat t c volume of the voids between the crystals does not exceedthirty two percent of the total volume occupied 'byvthe crystals. I

-12 Afcartridge comprisinga casing in theiformi of all-external shell and a central axial tube' therein so much smaller than theshell as'to-leave a s ace between the shell and the tube, said tu heingspervious 'tohq'uid hydrocarbon, and crysta between the casing and the tube which are so crushed and packedfor the purpose described that the volume of the voids between the crys tals does not 'exceednineteen per cent of the total volume occupied by the crystals.

13.j=A cartridge comprising a "casing in the form of an external shell and a central axial tube therein between which and the shell is a space, said tube being pervious to liquid hydrocarbon and crystalsof the kind described so crushed and packed into said space that the volume of the voids between the crystals does not exceed thirty-two per cent of the volume occupied by the c said tube moreover being of such imensions that it serves as a measure for introduction of hydrocarbon.

14, A cartridge comprising a casing in the.

form, of an external shell and a central axial tube therein between which and the shell is a space, said tube being pervious to liquid hydrocarbon and crystals of the kind described so crushed and acked into said space that the volume of t e voids between the crystals does not exceed thirty-two per cent .of the volume occupied by the c stals, said tube moreover being of such imensions that its internal volume is equal to the volume of hydrocarbon required to be introduced to prepare the cartridge for use.-

15. A method for the manufacture of hollow cartridges which consists in securingtogether an outer cartridge case closed 'at one end and an inner cylinder co-axial therewith which is pervious-to liquid and packing crystals of. an oxygen-carrying substance of the kind described into the annu- 'la r space between the cartridge and the porous inner cylinder by means of an annular feed worm which fits the annular stals, 4

space and is simultaneously oscillated longitudinally and rotated about-the axis of the cartridge.

16. A method for the manufacture of hollow cartridges which consists in securing together an outer cartridge case closed at one end and an inner cylinder co-axial therewith, which is pervions to liquid, supporting the inner cylinder upon a mandrel, and packing crystals of an oxygen-carrying substance of the kind described into the annular space between the cartridge and the porous inner cylinder by means of an annular feed worm which fits the annular space and is simultaneously oscillated longitudinally and rotated about the axis of the cartridge, and subsequently after the filling operation is completed removing. said mandrel from the inner cylinder.

In testimony whereof I afiix my signature.

ALEXANDER CRUlCKSl-IANK SCOTT. 

